RAW vs White balance

Started Nov 20, 2006 | Discussions thread
GordonBGood Veteran Member • Posts: 6,308
Re: interesting criticisms

ptodd wrote:

Perhaps if you have time you could download the software and do
your own tests, with all appropriate controls in place?

I might even do this myself sometime, but not right now...

Are you the original author?

I don't need the software, as I have my own on which I base my raw conversions that can be set to do the same thing.

There isn't a lot of point of repeating the experiments, as I don't have and won't be getting a DS and other cameras may behave differently.

I may have access to a K100D and/or eventually a K10D, and will be checking that ISO settings are accurate but won't be much concerned with the second range of tests other than that for my stated reasons. If I saw such a difference in ISO sensitivity that is not a factor of two as between the ISO 200 and ISO 400 shots, I would be looking for the reasons for this and aperture would be a very important parameter (I would have used full manual mode for these tests and stated aperture values).

As to the first range of tests showing a turned down sensitivity for very "warm" high red Tungsten WB shots, I wouldn't be surprised that this could be true for the reason of giving more Red channel headroom and that there is a private tag in the PEF file telling the raw convertor to adjust exposure for this after WB compensation. Again, full exposure values including aperture are an important part of confirming this.

Neither of these tests, other than the illogical results of the ISO sensitivity justify casting doubt on the useabiliy of PEF raw image files, especially when they are not backed up with full test details.

Regards, GordonBGood

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